ABCD

Example

A
C
C
10
C
B
C
13
A
B
C
17
_
_
6
 
 
A
B
C
_
_
_

Solution

A
C
C
10
C
B
C
13
A
B
C
17
14
20
6
 
 
A
B
C
6
9
2
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ABCD
ABCD

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